The killing of Anwar al-Awlaki, along with three of his compatriots, sends a powerful message to operational terrorists and extremist ideologues that God is not on their side. It isn’t clear, however, whether al-Qaeda in the Arabian Peninsula (AQAP), the group that Awlaki was associated with, has received the message. In a statement issued after Awlaki’s death, AQAP vowed: “O proud tribes: The blood of the Sheikh and his brothers will not go in vain; there are heroes behind him who do not sleep under oppression, and they will retaliate soon, with permission from Allah….We and the American are at war: we get them and they get us, and the end is for those who are patient [and]…are the ones who will be victorious.’’

That defiance and America’s resolve to kill terrorist leaders who pose threats to the U.S. homeland—even including American citizens—reflect the ongoing intensity of the struggle between Muslim militancy and a U.S. government bent on protecting American lives.

When I visited Yemen last year, I met with Awlaki’s friends and family. Although he was not widely known in Yemen except among relatives, security and intelligence services and informed Yemeni circles in the capital of Sana, he was well known among terrorists and their supporters worldwide. His aim was to instigate attacks against Western interests both on Western soil and elsewhere. His influence among a small but focused segment of Muslims in the West transformed AQAP, a local group with ideological and operational ties to al-Qaeda, to a sustained international threat.

Awlaki presented a serious threat for two reasons. First, he was a stunningly eloquent and convincing ideologue. Having worked both in the West and in Yemen, Awlaki knew how to operate in the Middle East and in the English-speaking world. He knew the mindset of both Middle Eastern and Western Muslims. Although his understanding of Islam was superficial and he was not a trained cleric, he was a master communicator. He tweaked his speeches, writings and exchanges to lure, convince, trap and control his followers. They were willing to kill and die for him. The rise in homegrown terrorism is attributable in part to Awlaki.

Awlaki's ideas propelled secondary-school students on both sides of the Atlantic to advocate, support and participate in violence. Canadian and British intelligence services detected students as young as fifteen years old who had been engaged by Awlaki. Many were counseled by elders, parents, teachers and the security services, but there are a few who remained solidly committed to Awlaki's ideals of death and destruction.

Second, Awlaki was a master in the use of the Internet. Although those inspired and instigated by Awlaki never met him face to face, his message will continue to find resonance long after his death. Of fifteen thousand websites and web forums that support terrorist and extremist activities, about ten thousand were on U.S.-based servers. Awlaki’s role model and mentor was Yusef al-Ayiri, the founder of AQAP and al-Qaeda’s web master. Like Ayiri, Awlaki wanted to be both an ideologue and an operational terrorist. A former bodyguard of Bin Laden, al Ayiri wrote more than thirty books including Crusaders’ War, the blueprint for fighting in Iraq. Awlaki's most influential lecture and book, Constants on the Path to Jihad, is based on al-Ayiri’s writings. Desperate to disrupt Awlaki’s influence, the U.S. government urged YouTube to shut down Awlaki’s videos in November 2010. Still, his thoughts and communication style will continue to influence others to commit murder and sabotage.

Educated both in the United States and in Yemen, Awlaki was the son of an agriculture minister and president of Sana’a University. With degrees in civil engineering and education in the United States, he was registered as a doctoral student in human resource development at George Washington University in 2001.

Awlaki began his preaching career in 1994 at Colorado State University in Fort Collins and continued after he moved to Denver in 1995 and San Diego, California, in 1996. Away from his congregation, Awlaki was a playboy who solicited prostitutes. He was arrested in San Diego in 1996 and 1997 and once in the Washington D.C. area.

Gradually, Awlaki got sucked into the extremist orbit. In 1998–1999, he was vice president of the Charitable Society for Social Welfare, a front for al-Qaeda run by Sheikh Abdul Majid al-Zindani. Although he came to the attention of the FBI around that time for links with the al-Qaeda procurement officer Ziyad Khalil and with the “blind sheikh” Omar Abdel Rahman, he was cleared. As imam at the Dar al-Hijrah mosque in Falls Church, Virginia, he came into contact with 9/11 hijackers Nawaf al-Hazmi, Khalid al-Midhar and Hani Hanjour, but it isn’t very likely they discussed operational details. The FBI interviewed Awlaki four times in the eight days following the 9/11 attacks, and the pressure forced him to relocate to the United Kingdom in March 2002. In the U.K., Awlaki was prolific on YouTube. According to reports, he influenced (among others) the July 7, 2005, London attackers. After Awlaki moved to Yemen, he joined Iman University in 2004 and was arrested in 2006. Although the U.S. government said Awlaki was arrested on charges of kidnapping an American official, he said it was due to his role as an arbitrator in a tribal dispute and was held longer at the behest of the FBI to investigate his links to the 9/11 attack. By June 2008, Awlaki launched www.anwar-alawlaki.com<http://www.anwar-alawlaki.com/> and built a relationship with Bin Laden’s secretary Nasir al-Wuhaishi, who had become head of AQAP. Having recognized his talent, AQAP consulted Bin Laden and appointed him to head external operations—terrorist attacks outside Yemen and Saudi Arabia.

Awlaki did not attend any formal Islamic education to become a religious cleric. But, using the Internet, he played a role among Western Muslims by providing answers to contemporary issues of injustice felt by them. His message resonated because of its “straightforward and brave” tone and content. Awlaki demonstrated how effectively cyber media could be used to radicalize susceptible audiences. In Yemen, though known in the cyber world, he was disregarded by the Yemeni officials as an inconsequential small fry. As the masses have not been accustomed to the cyber world in a Third World country such as Yemen, the majority did not recognize him. In death, he is a recognized radical throughout the world. But before he died, he created his persona and influence in the cyber world.

Professor Rohan Gunaratna is head of the International Centre for Political Violence and Terrorism Research at the S. Rajaratnam School of International Studies in Singapore, author of Inside Al-Qaeda (Columbia University, New York, 2002) and lead author of Pakistan: Ground Zero Terrorism (Reaktion, London, 2011)